This invention relates generally to electrical system condition assessment analyzers and more particularly, to methods and apparatus for detecting partial discharge (PD) in electrical systems.
Partial discharge events in an electrical system are pulsed releases of energy that propagate out from their site of origin. The propagation occurs according to the structure surrounding the partial discharge events. An internally generated partial discharge pulse appears and propagates at the end regions of an electrical device, such as a high or low voltage bushing and generator end windings, as specific pulse waves in accordance with the surrounding structure, the location of the origin of the pulse, and the pulse characteristics. Although partial discharge analysis has been used for many years on various electrical equipment, at least some data collections and data interpretations are performed substantially manually using labor-intensive techniques.
Specifically, most known methods of determining Partial Discharge Inception Voltage (PDIV), that is, that voltage associated with the electrical equipment of interest wherein partial discharge activity substantially initiates, include installation and removal of measuring equipment during equipment service outages. Also, specifically, most known methods of partial discharge data interpretation typically include using extensive analysis to interpret the data collected in conjunction with, and in reference to, data collected as a function of differing environmental conditions associated with the electrical equipment. Such extensive analysis typically requires obtaining subject matter experts in the form of highly specialized industry professionals which can be time-consuming and expensive. Moreover, such analyses are neither automated nor substantially close to a present time, that is, close to real time and/or an instantaneous time of such PD activity. For example, such analyses may nor occur until days after such PD activity. Similar issues are also associated with most known methods of determining Partial Discharge Extinction Voltage (PDEV), that is, that voltage associated with the electrical equipment of interest wherein partial discharge activity substantially extinguishes.